Field of the Invention
The present invention relates to an imaging module in which a solid-state imaging element is connected to an electrical cable via a flexible wiring substrate, and a catheter configured using the imaging module.
Description of Related Art
A lot of imaging modules in which an imaging unit having a solid-state imaging element is assembled to the tip of an electrical cable are adopted for catheters.
The imaging modules have, for example, a configuration in which a flexible wiring substrate (FPC) having a solid-state imaging element mounted thereon and an objective lens unit are housed within a tubular metal frame member and the solid-state imaging element is electrically connected to an electrical cable via the flexible wiring substrate.
In an imaging element shown in Japanese Unexamined Patent Application, First Publication No. 2011-217887, a flexible wiring board (FPC) having an imaging element chip (solid-state imaging element) mounted at a central portion thereof is electrically connected to a signal cable. The wiring board is bent to a side opposite to the imaging element chip at both ends in a location where the imaging element chip is mounted, and a block for supporting and guiding the wiring board is provided in a space surrounded by a central portion and an extension portion of the wiring board.
In an imaging module shown in Japanese Unexamined Patent Application, First Publication No. 2013-214815, a flexible wiring substrate (FPC) having a solid-state imaging element at a central portion thereof is connected to an electrical cable. The flexible wiring substrate is bent to a side opposite to the solid-state imaging element, and an internal space surrounded by the element mounting portion and a rear piece is filled with resin that supports the flexible wiring substrate.
In the imaging element shown in Japanese Unexamined Patent Application, First Publication No. 2011-217887, it is necessary to fix the extension portion of the wiring board to the block in order for it to be connected to the signal cable, and it is difficult to reduce the diameter thereof due to the presence of the block. For example, it is difficult to set the outside dimension of the imaging module portion to 2 mm or less. Additionally, there is concern that the wiring board may be disconnected due to warpage caused by a difference in coefficient of thermal expansion from that of the block.
In the imaging module shown in Japanese Unexamined Patent Application, First Publication No. 2013-214815, it is difficult to make a diameter small without causing disconnection in the bent portion of the flexible wiring substrate.